---
id: react-native
title: Building a React Native Plugin
---
import useBaseUrl from '@docusaurus/useBaseUrl';
import Link from '@docusaurus/Link';

:::caution
This section of the tutorial requires React Native 0.62 or higher.
:::

Once you've connected Flipper to a React Native application, writing your own Flipper plugin can be done without reaching into the native world.

To expose Flipper to the JavaScript world, the React Native module `react-native-flipper` needs to be installed in the hosting application by running `yarn add react-native-flipper` and `cd ios && pod install`. If you are developing a plugin that is distributed as NPM package, make sure to add this to the installation instruction of your package as well!

Registering a new plugin is done by importing `addPlugin` from `react-native-flipper` and providing it an object that at least implements the method `getId` (the plugin id that should be used in the desktop plugin as well to make the connection) and two event handlers for the `onConnect` and `onDisconnect` events. The `onConnect` and `onDisconnect` events are triggered every time the plugin becomes (in)active in the Flipper desktop application. If the plugin is a <Link to={useBaseUrl("/docs/extending/create-plugin#background-plugins")}>background plugin</Link>, the events are triggered typically only once (they might be triggered never, if the Desktop user didn't enable the plugin, or multiple times if they enabled or disabled the plugin a few times).

The `onConnect` callback receive a `connection` which can be used to communicate with the backend:

```javascript
import {addPlugin} from "react-native-flipper"

addPlugin({
  getId() {
    return 'ReactNativeExamplePlugin';
  },
  onConnect(connection) {
    mammmals.forEach(({ title, pictureUrl }, index) => {
      connection.send('newRow', {
          id: index,
          title,
          url: pictureUrl
      })
    })
  },
  onDisconnect() {
  }
})
```

You may want to store the connection somewhere to be able to send more events as long as `onDisconnect` event hasn't been fired.

The `connection` object can also be used to listen to messages coming from the Desktop plugin. See <Link to={useBaseUrl("/docs/extending/create-plugin")}>Client Plugin API</Link> for details.

An example plugin to play a little Tic-Tac-Toe between the Flipper Desktop and a React Native app can be found inside this repository as well (run `yarn && yarn android` in `react-native/ReactNativeFlipperExample` to start the test project):

 * The React Native JavaScript based plugin implementation - [FlipperTicTacToe.js](https://github.com/facebook/flipper/tree/main/react-native/ReactNativeFlipperExample/FlipperTicTacToe.js)
 * The Flipper Desktop plugin implementation - [rn-tic-tac-toe/index.tsx](https://github.com/facebook/flipper/blob/main/desktop/plugins/public/rn-tic-tac-toe/index.tsx)
